i4 READINGS IN BIOLOGICAL SCIENCE 



ever they succeed in overcoming this tendency by the use of drugs, usually 

 bear a female child. 



A woman does not bear children after the age of fifty, and with the 

 majority menstruation ceases at forty. Woman is, however, the only animal 

 that has monthly periods; consequently she alone has what arc called moles 

 in the womb. This mole is a shapeless and inanimate mass of flesh that re- 

 sists the point and the edge of a knife; it moves about and it checks menstru- 

 ation, as it also checks births: in some cases causing death, in others grow- 

 ing old with the patient, sometimes when the bowels are violently moved 

 being ejected. A similar object is also formed in the stomach of males, 

 called a tumour. . . . 



The latter (women who do not menstruate), however, do not have chil- 

 dren, since the substance in question (menstrual fluid) is the material for 

 human generation, as the semen from the males acting like rennet col- 

 lects this substance within it, which thereupon immediately is inspired 

 with life and endowed with body. Hence when this flux occurs with 

 women heavy with child, the offspring is sickly or still-born or sanious, 

 according to Nigidius. (The same writer holds that a woman's milk does 

 not go bad while she is suckling a baby if she has become pregnant again 

 from the same male.) It is stated, however, that the easiest conceptions are 

 when this condition is beginning or ceasing. We have it recorded as a sure 

 sign of fertility in w^omen if when the eyes have been anointed with a drug 

 the saliva contains traces of it. 



■> >><< <■ 



EXCERPTS FROM The FiTst Observations on 

 ^^Little AimnaW Protozoa and Bacteria hi Waters * 



ANTONY VAN LEEUWENHOEK 

 1ST OBSERVATION ON RAIN-WATER 



In the year 1675, about half-way through September (being busy with 

 studying air, when I had much compressed it by means of water), I dis- 

 covered living creatures in rain, which had stood but a few days in a new 

 tub, that was painted blue within. This observation provoked me to in- 

 vestigate this water more narrowly; and especially because these little 

 animals were, to my eye, more than ten thousand times smaller than the 

 animacule which Swammerdam has portrayed, and called bv the name of 

 Water-flea, or Water-louse, which you can see alive and moving in water 

 with the bare eye. 



Of the first sort, that I discovered in the said water, I saw, after divers 



• From Aritony Van Leeuwenhoek and His ''Little Ani^nals'' by Clifford Dobell. 

 Reprinted by permission of Harcourt, Brace and Company, Inc. 



